‘optimization’ affects buildtype

[kloetzl]

Here is some behavior which I find very confusing.

project('helloworld', 'c', version : '0.2', license : 'GPL3',
    default_options : [
        'buildtype=release',
        'optimization=2',
        'b_ndebug=if-release'
    ]
)

Setting optimization to 2 disables the release buildtype. Even setting it explicitly doesn't help.

% meson setup --buildtype=release dir
…
Option buildtype is: custom [default: release]

This also breaks the if-release feature. I think the above configuration simply should result in a release buildtype with -O2 instead of -O3.

[jpakkane]

The semantics of buildtype are roughly "if release, set options x, y and z to values a, b and c". You should either set all individual options yourself or just set the build type.

This is due to backwards compatibility. If we were to design this from scratch, buildtype would not be a standalone option, just a shortcut to set the other options.

[kloetzl]

Thank you for looking into this. I think there are multiple facets to the issue.

The semantics of buildtype are roughly "if release, set options x, y and z to values a, b and c".

If we were to design this from scratch, buildtype would not be a standalone option, just a shortcut to set the other options.

Well, the behavior you are describing is a shortcut, just as it should be in my opinion. If release use -O3, unless overridden. Above, I want to change -O3 to -O2.

Now the weird thing is that setting optimization changes the buildtype. I don't see why it should. Furthermore, note that all these options are default options. Thus configuring the build via the commandline should take precedence. Interestingly, --buildtype=release doesn't work, but -D optimization=3 does.

[yunlingz]

Agreed, I just want to change the optimization level from O3 to O2, but the buildtype
will be changed to custom, not keep release.

I think that maybe other opts should affect buildtype, but optimization should not, it's very special.

[jpakkane]

As said, that is due to backwards compatibility. But if at all possible do not depend on buildtype, but instead look at specific settings instead.